C# – How to force HTTPS using a web.config file

asp.netchttpsiisweb.config

I have searched around Google and StackOverflow trying to find a solution to this, but they all seem to relate to ASP.NET etc.

I usually run Linux on my servers but for this one client I am using Windows with IIS 7.5 (and Plesk 10). This being the reason why I am slightly unfamiliar with IIS and web.config files. In an .htaccess file you can use rewrite conditions to detect whether the protocol is HTTPS and redirect accordingly. Is there a simple way to achieve this using a web.config file, or even using the 'URL Rewrite' module that I have installed?

I have no experience with ASP.NET so if this is involved in the solution then please include clear steps of how to implement.

The reason for me doing this with the web.config and not PHP is that I would like to force HTTPS on all assets within the site.

Best Answer

You need URL Rewrite module, preferably v2 (I have no v1 installed, so cannot guarantee that it will work there, but it should).

Here is an example of such web.config -- it will force HTTPS for ALL resources (using 301 Permanent Redirect):

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.webServer>
        <rewrite>
            <rules>
                <clear />
                <rule name="Redirect to https" stopProcessing="true">
                    <match url=".*" />
                    <conditions>
                        <add input="{HTTPS}" pattern="off" ignoreCase="true" />
                    </conditions>
                    <action type="Redirect" url="https://{HTTP_HOST}{REQUEST_URI}" redirectType="Permanent" appendQueryString="false" />
                </rule>
            </rules>
        </rewrite>
    </system.webServer>
</configuration>

P.S. This particular solution has nothing to do with ASP.NET/PHP or any other technology as it's done using URL rewriting module only -- it is processed at one of the initial/lower levels -- before request gets to the point where your code gets executed.

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